The present invention relates to control lever mounting systems and, more particularly, to control lever mounting systems used to attach speed control levers on bicycle frame tubes.
Although many types of multi-speed bicycles carry speed control levers mounted on their handlebar stems, some types of lightweight racing and touring bicycles include control levers mounted on their frame downtubes. With the latter, the control levers typically are mounted on bosses which protrude sidewardly from the tube along a horizontal axis. The bosses each include a base which is arcuately shaped to conform to the curvature of the downtube and is attached to the tube by brazing or welding. A disadvantage of such construction is that the brazing or welding operation is time-consuming and labor intensive thereby adding measurably to the overall cost of fabricating the bicycle frame.
In an alternate method of mounting speed control levers on the tube of a bicycle frame, a first boss member includes a bore the receives a screw which extends through the tube and threads into a bore of a second boss member. Ashesive is applied to the boss members and tube, and the screw holds the boss members together until the adhesive sets up.
In another known mounting system, the bosses include cylindrical stems that extend into the tube and a complementary connecting member, such as a threaded shank, engages threaded bores in the stems. The bases conforming to the tube wall and covering the tube holes are in the form of washers retained by collars on the bosses. Engagement of the complementary connecting member holds the bosses and bases against the tube. The design of those speed control mechanisms is such that an inordinant amount of manual labor is required to make the threaded connections between the boss members, and such connections are susceptible to fouling.
Accordingly, there is a need for a speed control lever mounting system which is relatively simple in construction and can be mounted directly onto the tube of a bicycle frame with a minimum of manual labor. Furthermore, such a mounting system should be positively attached to the frame tube and able to withstand rugged environmental conditions and vibrations imposed on the bicycle frame.